In recent years, exhaust gas regulations against automobiles have been tightened. For this reason, a fuel injection valve mounted on an internal combustion engine for an automobile is required to atomize fuel spray, inject the fuel spray toward on-target positions (for example, dual intake valves), thereby suppress adhesion fuel to an inner-wall surface of an intake pipe and others, and reduce the amount of noxious exhaust gas HC (hydrocarbon) from the internal combustion engine.
With regard to a conventional fuel injection valve, a method for accelerating the atomization of fluid with a relatively simple configuration has been disclosed. The atomization method is a method of forming a film of fluid injected from a nozzle hole and accelerating atomization while the fluid film expands and thereby splits (refer to JP-A No. 3518/2004).
Another document discloses a fuel injection valve of forming a nozzle plate having nozzle holes into a bowl shape to suppress deformation of the nozzle plate, thereby preventing injected fuel spray from becoming bad conditions, and directing the injected spray accurately (refer to JP-A No. 317607/1997).
By the aforementioned conventional technologies, it is possible to atomize fuel injected from a single fuel injection nozzle hole or a set of fuel injection nozzles. However, in the case of a fuel injection system where fuel sprays injected from a plurality of nozzle holes are integrated into sprays directed toward two directions for dual intake valves of an internal combustion engine, interference among a plurality of sprays a fuel occurs. Such interference becomes a cause of hindering atomization of fuel spray. The aforementioned conventional technologies have not described sufficiently to improve such a problem. Further, although the latter of the conventional technologies discloses the method for stabilizing fuel spray, it has not disclosed a method for accelerating atomization of fuel spray injected from a nozzle.
By the way, according to the combustion experiments for an internal combustion engine with two (dual) intake valves conducted by inventors for the present invention, obtained is the result that the effect of improving combustion can be obtained when the fuel injection is directed closer to the inside than the centers of two intake valves of the internal combustion engine and moreover a fuel fluid film is spread thinly and widely on the intake valves.
The first object of the present invention is to prevent interference between atomized fuel sprays, thereby prevent coarse particles of fuel sprays from forming and form two(dual)-direction spray with a high spreadability.